Scientific Proof: Sexuality Is Genetic

Slate Human Nature column, you've englightened me yet again:

Lesbian brains differ from straight women's brains. Last year, a study showed that gay men, like straight women and unlike straight men, processed a male pheromone in a sex-related part of the brain (the hypothalamus) but processed a female pheromone in a scent-related part of the brain. Now the authors of that study report differences among women: 1) Lesbians, like straight men, prefer the female pheromone and find it less irritating than the male pheromone. 2) Straight women find the female pheromone more irritating. 3) Straight men and women process same-sex pheromones in the scent area but process opposite-sex pheromones in the hypothalamus. 4) Lesbians process pheromones of both sexes in the scent area. Interpretations: 1) Sexual orientation is biologically based, not a choice. 2) Sexual orientation is more biologically based in men than in women. (For a summary of the study of gay men, click here. For Human Nature's take on gay marriage, click here.)